The present invention relates generally to rim holding tire changers and more particularly to a tire rotation and handling device for use in connection with passenger vehicle rim holding tire changers.
It will be appreciated by those skilled in the art of designing and manufacturing equipment used to change the tubeless tires mounted on the rims of cars, light trucks and other vehicles that such equipment must perform quickly and efficiently in order to be competitive in the marketplace. Modest improvements in the industry, can thus become significant.
The type of equipment for which Applicant's invention is designed is known generally in the industry as a rim holding tire changer. Examples of the type equipment involved are the rim holding tire changers manufactured by Hennessy Industries, Inc., Applicant's assignee, and marketed under the trademarks "COATS.RTM." and "AMMCO.RTM." including the COATS.RTM. models 5030A and the model 5060A-E and 5060AX-EX. However, there are many manufacturers of such equipment, including FMC Corporation of Chicago, Ill., Corghi of Correggio, Italy and Sice of Correggio, Italy. Equipment of this type has been readily available in the market for many years, is the subject matter of numerous patents and has been described in a variety of publications, bulletins, brochures, operating and instruction manuals, and the like. One such machine is illustrated in the design patent issued to Applicant as co-inventor in U.S. Design Pat. No. 293,916.
In the normal tire changing procedure, the operator places a rim on the table of the rim holding tire changer, secures the rim to the table, places a tire over the rim, mounts the tire on the rim by using a mount/dismount head to force the bead over the rim and then fills the air chamber of the tire with air to inflate the tire. This procedure is described in detail in U.S. patent application Ser. No. 08/516,129, the substance of which is incorporated herein by reference, and which is assigned to the assignee of the present invention. However, assuming that the customer is not buying a new rim, before this procedure begins, the operator must first remove the customer's old tire from the rim.
A tubeless tire mounted on a rim seals the air inside the chamber of the tire by "seating" the bead of the tire against the "hump" of the rim. This seal is maintained by substantial pressure both from the air inside the chamber of the tire and the load of the vehicle on which the tire is mounted. After many miles of travel, the seal becomes very difficult to break. The tire sticks to the rim and must be forced or pried loose in order to remove the old tire so that it can be replaced with a new one. To assist in breaking the seal between the tire bead and the rim, rim holding tire changers have been provided with a device called a "bead loosener shoe". A bead loosener shoe is an arcuate wedge that has a smooth edge generally in the shape of a portion of the rim at the point where the bead of the tire seats on the rim. The shoe is pivotally mounted on an arm that allows an operator to bring the shoe into contact with the tire/rim at the point of seal and the shoe is then forced between the tire and the rim to break the seal at the point of contact. The tire must then be rotated so that the next section of the seal can be broken. To do this, the operator must roll the tire away from the shoe, lift the tire and spin it so that when it is rolled back into contact with the shoe, a different section of the seal will be exposed to the shoe. This process requires the operator to lift the tire from an awkward position, putting unwanted pressure and strain on the back of the operator. The procedure is also time consuming.
Since the tire must be rotated several times to break the seal completely around the perimeter of the rim, and the seal must be broken on both sides of the rim, the process is repeated several times in the changing of a single tire. An operator who performs this process on a full time basis will experience fatigue and occasionally may be injured on the job. There is not currently available any device to assist in this process or to relieve some of the pressure and strain caused by the process.
Tire changers designed for use in changing the tires of large trucks, construction equipment and the like, have employed devices to assist with the lifting and spinning of the tires due to their weight. One such device is a roller mechanism employed by applicant's assignee in its HIT 6000 tire changer. However, no such device has been used on a tire changer used to change the tires of passenger vehicles, cars and light trucks.
What is needed then is a lift and spin device on a passenger vehicle tire changer that will reduce or eliminate the necessity of lifting and spinning the tire when using a shoe to break the seal between the tire and the rim.
In a number of passenger vehicle rim holding tire changers currently on the market, foot pedals are used to apply air pressure within the chamber of a tire that is being mounted on a rim. Thus, the operator is working primarily from one side of the device. The provision of a device on a passenger vehicle rim holding tire changer to assist with the lift and spin process, to be effective then, must be properly orientated to the foot pedals so that the operation of the device can be conducted efficiently. Such a device is presently lacking in the prior art.